The invention relates to an electrical lamp base and socket assembly for mechanically holding and supplying power to an electrical lamp having a vitreous envelope, the base and socket assembly allowing mainly axial motion for the lamp and avoiding any turning motion over an angle of greater than 90 degrees during its insertion into and removal from the socket. The invention relates also to a method of operating an electrical lamp base and socket assembly.
The present electrical lamp base and socket assembly can be utilized favorably with several kinds of electrical lamps, i.e. incandescent lamps, discharge lamps, and especially also with electrodeless high intensity discharge lamps.
In the case of typical lamp bases and sockets, generally, a turning motion is employed during the insertion of the lamp into or the removal of it from the socket. In some cases, e.g. in the case of an electrodeless high intensity discharge lamp with an outer induction coil, the performance of such turning motion is relatively difficult because the outer envelope of the lamp has to be surrounded by a close-fitting induction coil which limits the area of the envelope which can be gripped during the turning of the lamp. Thus, there is sometimes a definite demand for lamp bases and socket assemblies which can be used by moving the lamp in the direction of its axis and avoiding any turning motion or at least over a certain maximum value of the turning angle.
Additionally, because of the outer surrounding coil, for an electrodeless HID lamp, there is a further requirement that the base and socket assembly have a smaller outer diameter than the lamp envelope so as to allow movement through the outer coil. For an example of this dimensional relation between the outer envelope and the induction coil of an electrodeless HID lamp, reference is made to U.S. Pat. No. 5,150,015 issued to Heindl et al. on Sep. 22, 1992.
Electrical lamp base and socket assemblies of the kind mentioned in the introductory paragraph and for application with incandescent lamps are well-known as the bayonet lamp base and lamp holder. In the case of bayonet lamp bases and lamp holders, the base is usually made of metal and has two protruding pins on its lamp base for engaging two L-shaped slots in the lamp holder, providing in such a way the mechanical holding and power supply of the incandescent lamp. These protruding pins however increase the outer size of the lamp base and would thus be inappropriate for an application involving an outer envelope which must fit within an induction coil.
In fields different from that of electric lamps, there are several known kinds of latch mechanisms for mechanically holding one or another component part, (e.g. in the case of the locking mechanism of cabinet doors). The component part, a locking dowel, is fixed on the door and has to be inserted into and removed from a latch mechanism by axial motion. Mechanical holding of this kind is mentioned in the U.S. Pat. No. 2,637,576.